Re: [tlug] Linux Stalling Question

["Stephen J. Turnbull" <stephen@example.com>]

>>>>> "David" == David Bennett <davidbennett1979@example.com> writes:

    David> Every once in awhile I find my Linux box "stalled." 
    David> Frozen. The monitor won't flick on, and none of my services
    David> (ssh, http) will respond (hence I assume it is a true
    David> freeze.) I would like to find out what is happening but I
    David> am not sure where to start. Can someone recommend a few
    David> logs I could take a look at,

No, this is a kernel problem.  This is not DOS or Windows 9x; nothing
else can freeze the whole system.  Under normal circumstances, the
kernel does not log what it's doing; it gets called hundreds or
thousands of times per second, you can't afford that (it would be like
removing your CPU and installing one that cost half as much ;-).  You
should look at the last line of all logs you've got and find the most
recent one, but it's unlikely that that app is the one that's causing
the problem.

My guess is that you've got a badly written driver that's inflooping
with interrupts disabled.  Get rid of services for hardware you don't
need, and if that doesn't help, get rid of hardware you can live
without for a while.  I don't know how MythTV works, but I would start
with that unless somebody who knows what they're talking about
suggests something else.

You could try a different kernel.  Build your own or upgrade to the
vendor's most recent or something.

It's possible you've got a weird hardware problem, or a corrupted
program.  fsck all your disks, enable the BIOS memory check, reseat
all the cards and connectors in the box, etc.

    David> or where I would be able to find the source as to this
    David> freezing? (alternatively what the system is doing before it
    David> freezes.)

If your kernel is debug-enabled, then Alt-SysRq-t will list the
current tasks.  SysRq is also labeled PrintScreen or some variant on
many keyboards for sysrq.txt, or find it in the kernel sources
Documentation directory.  Alt-SysRq-s (write disk buffers to
hardware), Alt-SysRq-u (unmount disks), Alt-SysRq-r (reboot) is often
a useful sequence.

*****

If that doesn't work, download XEmacs sources and try the instructions
in etc/InstallGuide.  (You can also preview them via ViewCVS,
http://cvs.xemacs.org/Viewcvs.cgi/XEmacs/xemacs/etc/InstallGuide, but
they must be installed on your computer to be loaded into mystical memory.)

-- 
School of Systems and Information Engineering http://turnbull.sk.tsukuba.ac.jp
University of Tsukuba                    Tennodai 1-1-1 Tsukuba 305-8573 JAPAN
               Ask not how you can "do" free software business;
              ask what your business can "do for" free software.